Method for comprehensive utilization of sandy kaolin tailings

Abstract

The application discloses a comprehensive utilization method of sandy kaolin tailings, which comprises the following steps: step (1), screening the sandy kaolin tailings into two particle size grades of +20 mesh coarse sand and -20 mesh fine sand; step (2), adopting a high-alumina ceramic ball mill to grind the +20 mesh coarse sand, performing grading treatment after grinding, removing -140 mesh fine powder to obtain a grading product, and then performing magnetic separation on the grading product to remove magnetic minerals and obtain low-iron quartz sand for photovoltaic glass; step (3), adopting the high-alumina ceramic ball mill to grind the -20 mesh fine sand, performing grading and gravity separation treatment after grinding, and then performing magnetic separation, finally performing positive flotation on the obtained magnetic separation concentrate under neutral conditions to remove impurity minerals and obtain the low-iron quartz sand for photovoltaic glass; and step (4), performing magnetic separation, desliming, drying, powder grinding and grading treatment on -140 mesh fine sand generated in the process of treating the +20 mesh coarse sand and the -20 mesh fine sand to obtain silicon micro powder.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of comprehensive utilization of sandy kaolin tailings, and particularly relates to a comprehensive utilization method of sandy kaolin tailings. BACKGROUND

[0002] China is rich in kaolin resources, with a proven reserve of 2.91 billion tons, of which the sandy kaolin resources account for about 60% of the proven reserves. The ore types of kaolin can be divided into hard kaolin, soft kaolin and sandy kaolin according to the texture, plasticity and content of sand of kaolin ore. The content of sand in sandy kaolin is more than 50%. However, most of the current sandy kaolin processing enterprises only focus on the beneficiation and deep processing of kaolin, and less on the recycling of a large amount of tailings generated in the processing process. Most of them are sold at low prices as building sand, causing waste of non-renewable resources. The main mineral composition of sandy kaolin tailings is quartz, containing a small amount of impurities such as kaolinite, feldspar, mica, hematite, zircon and rutile, which has the feasibility of purifying and preparing low-iron quartz sand.

[0003] The solar photovoltaic power generation industry in China is developing rapidly. As an important component of solar cell modules, the demand for photovoltaic glass has increased significantly. Quartz sand is one of the main raw materials for producing photovoltaic glass. About 0.71 tons of low-iron quartz sand is needed to produce one ton of photovoltaic glass, and the quality of the quartz sand has an important influence on the quality of the photovoltaic glass. However, at present, there are few natural high-quality low-iron quartz sand resources in China, mainly distributed in Guangdong Province, Guangxi Zhuang Autonomous Region, Anhui Province, Hainan Province and other places. In the future, with the growth of the production capacity of ultra-white glass for solar cells, high-quality quartz sand with limited distribution will become a relatively scarce resource. However, a large amount of kaolin tailings containing quartz is generated after the separation of sandy kaolin, which is not efficiently utilized at present. Therefore, it is of great significance for the development of the photovoltaic industry in China to use kaolin tailings to prepare low-iron quartz sand for photovoltaic glass.

[0004] The maturely applied low-iron quartz sand purification process for photovoltaic glass in industry includes physical methods such as grading, desliming, scrubbing, grinding, magnetic separation, gravity separation, ultrasonic scrubbing and flotation, and chemical methods such as pickling or acid leaching.

[0005] The current photovoltaic sand quality requirement is implemented in the industry standard JC / T2314-2015 Siliceous Raw Material for Photovoltaic Glass. However, there are deviations in the implementation process of various enterprises. The quality requirements of photovoltaic glass for photovoltaic sand mainly reflect in the aspects of Fe2O3 content, TiO2 content and particle size, etc. The most important one is to control the content of Fe2O3. The main difference between quartz sand for photovoltaic glass and quartz sand for ordinary glass is the amount of iron content. The Fe2O3 content of photovoltaic sand is required to be not more than 0.01% (the industry standard requires that the Fe2O3 content is less than or equal to 0.008%). This is because iron oxide causes glass to be colored, which affects the light transmittance of glass. In addition, iron oxide causes the upper and lower layers of glass liquid to have a significant temperature gradient, which makes the convection of glass liquid in the melting furnace difficult, and increases the difficulty of melting and refining. Therefore, controlling the iron content in quartz sand is the key to the production of photovoltaic sand. The TiO2 content of photovoltaic sand is required to be not more than 300ppm. Because titanium oxide will cause glass to be colored, which reduces the light transmittance and transparency of glass. The particle size and gradation of photovoltaic sand will also affect the quality of photovoltaic glass. The particle size requirement is +0.71mm = 0%; 0.71-0.1mm ≥ 95%; -0.1mm ≤ 5%.

[0006] At present, in the utilization technology of sandy kaolin tailings, a method for preparing building sand, ordinary float glass sand, photovoltaic sand and quartz powder for TFT-LCD glass substrate from sandy kaolin tailings is provided. However, there are still some problems and deficiencies:

[0007] (1) The grinding of quartz sand generally uses metal medium (steel ball or steel rod) grinding. The surface of quartz sand is caused "iron secondary pollution" during the grinding process, which makes it difficult to prepare low-iron quartz sand by physical method. At the same time, the precise control of the grinding process cannot be realized.

[0008] (2) The different particle size tailings are not analyzed in depth, and the occurrence state of impurity minerals and impurity elements is not understood, so the targeted development of purification process cannot be realized, which leads to the low utilization level of sandy kaolin tailings resources.

[0009] (3) The flotation process is an effective means to remove impurities such as feldspar, mica and iron-containing minerals in quartz sand. However, the flotation environment needs to be in an acidic environment and add organic reagents for flotation. This process has high requirements for wastewater treatment. Acid leaching is a chemical beneficiation process, which can greatly improve the removal rate of iron elements. Common acids include HF, H2SO4, HCl, HNO3 and H2C2O4. A large amount of common sand in China needs to be purified by acid leaching process, which inevitably causes certain harm to the environment and the occupational health of workers. SUMMARY

[0010] Therefore, the main purpose of the present application is to provide a comprehensive utilization method of sandy kaolin tailings.

[0011] To achieve the above object, the technical scheme of the present application is as follows:

[0012] The embodiment of the present application provides a comprehensive utilization method of sandy kaolin tailings, comprising the following steps:

[0013] Step (1), the sandy kaolin tailings are screened into two particle size grades of +20 mesh coarse sand and -20 mesh fine sand;

[0014] Step (2), the +20 mesh coarse sand is ground by a high-alumina ceramic ball mill, and after grinding, the coarse sand is subjected to classification treatment to remove -140 mesh fine powder, and the classified product is subjected to magnetic separation to remove magnetic minerals, thereby obtaining low-iron quartz sand for photovoltaic glass;

[0015] Step (3), the -20 mesh fine sand is also ground by a high-alumina ceramic ball mill, and after grinding, the fine sand is subjected to classification and gravity separation treatment, and then subjected to magnetic separation, and finally the obtained magnetic separation concentrate is subjected to positive flotation under neutral conditions to remove impurity minerals, thereby obtaining low-iron quartz sand for photovoltaic glass;

[0016] Step (4), the -140 mesh fine sand generated in the process of treating the +20 mesh coarse sand and the -20 mesh fine sand is subjected to magnetic separation, desliming, drying, grinding and classification treatment, thereby obtaining silicon micro powder.

[0017] In the above scheme, in the step (1), the sandy kaolin tailings have a maximum particle size of 2 mesh, a moisture content of less than 10%, a SiO2 content of greater than 95%, an Al2O3 content of less than 2%, and an Fe2O3 content of less than 0.3%.

[0018] In the above scheme, in the steps (2) and (3), the +20 mesh coarse sand is ground by a high-alumina ceramic ball mill, the grinding concentration is 45% to 60%, the ceramic ball filling rate is 40% to 45%, and the high-alumina ceramic ball has an Al2O3 content of greater than 90%; the -20 mesh coarse sand is ground by a high-alumina ceramic ball mill, the grinding concentration is 45% to 60%, the ceramic ball filling rate is 40% to 45%, and the high-alumina ceramic ball has an Al2O3 content of greater than 90%.

[0019] In the above scheme, in the step (3), the product in the grinding process is classified by a cyclone, the underflow of the cyclone is fed into a high-frequency screen for screening, the +35 mesh product is returned to the ball mill for recycling grinding, the overflow of the cyclone and the undersize product of the high-frequency screen are fed into a drum screen, the +35 mesh product on the drum screen is combined with the +35 mesh product on the high-frequency screen and returned to the ball mill for recycling grinding, and the undersize product of the drum screen is a -35 mesh qualified product; the -35 mesh grinding product is subjected to hydraulic classification to remove -140 mesh fine powder to obtain a classified product; the classified product is configured into a slurry with a concentration of 25%-30% and fed into a spiral chute for gravity separation treatment; the gravity separation product is further subjected to magnetic separation, configured into a slurry with a concentration of 25%-35%, and adjusted to a pH value of 7-9, and then a cationic collector and sodium oleate are added to perform neutral positive flotation to obtain low-iron quartz sand for photovoltaic glass.

[0020] In the above scheme, in the step (2), the particle size of the grinding product in the grinding process is required to be less than 40 mesh, and the particle size is controlled to be less than 40 mesh to achieve sufficient dissociation; the -40 mesh grinding product is subjected to hydraulic classification to remove -140 mesh fine powder to obtain a classified product; the classified product is configured into a slurry with a concentration of 25%-30% and fed into a spiral chute to remove heavy minerals to obtain a gravity separation product; and the classified product is subjected to magnetic separation to remove magnetic minerals in the classified product to obtain low-iron quartz sand for photovoltaic glass.

[0021] In the above scheme, in the steps (2) and (3), the particle size of the classified product is required to be controlled to have a -140 mesh content of less than 5%; the magnetic separation is 3 stages, and the magnetic field strength of the first stage is 0.3-0.6 T, the magnetic field strength of the second stage is 1.0-1.3 T, and the magnetic field strength of the third stage is 1.4-1.6 T.

[0022] In the above scheme, in the steps (2) and (3), the first stage is a medium magnetic separation, the magnetic field strength is 0.3-0.6 T, the second stage is a strong magnetic separation, the magnetic field strength is 1.0-1.3 T, and the third stage is a magnetic separation, the magnetic field strength is 1.4-1.6 T.

[0023] In the above scheme, in the step (4), the -140 mesh fine sand is subjected to magnetic separation, the magnetic field strength is 1.3-1.6 T, and a magnetic separation concentrate is obtained; the magnetic separation concentrate is deslimed to remove -400 mesh fine slime to obtain 140-400 mesh fine sand; the obtained fine sand is dewatered by a belt vacuum filter to have a water content of less than 10%, and then dried by a drum dryer to have a water content of less than 0.5%; the dried fine sand is fed into a ball mill for dry grinding, and the silicon powder after grinding is classified by a classifier, the relatively coarse particles are returned to the ball mill for regrinding to form a closed circuit, and silicon powder with a required particle size specification is obtained.

[0024] In the above scheme, in the steps (2) and (3), according to Determine the optimal ball milling time t in the ball mill; wherein, p is the density of quartz sand, Q is the total amount of ball mill, V0 is the effective volume of ball mill, C is the grinding concentration, R is the return sand ratio mark, v is the volume of slurry passing through the ball mill per unit time, V1 is the volume of slurry in the ball mill.

[0025] Compared with the prior art, the high-aluminum ceramic ball mill is used for grinding quartz sand, the "secondary iron pollution" formed by the iron-containing grinding medium on the surface of the quartz sand is avoided, the grinding particle size is reasonably controlled, the dissociation of quartz and gangue minerals is accurately controlled, the high-efficiency purification of quartz sand is realized, the low-iron quartz sand for photovoltaic glass is prepared, the neutral flotation process is used, the quartz sand is purified by positive flotation, the green and environmental protection process is realized, the low-iron quartz sand for photovoltaic glass is prepared, and the environmental protection and occupational health hazards caused by the traditional process using acid flotation or chemical beneficiation are solved; through the process mineralogy research, the occurrence state of impurity minerals and impurity elements is found out, different beneficiation processes are used for grading and classification comprehensive utilization, and the effective utilization rate and added value of kaolin tailings are improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings described herein are used to disclose a further understanding of the present application, constitute a part of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0027] Figure 1 A flow chart of a comprehensive utilization method of sandy kaolin tailings is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0029] The same or similar reference numerals in the drawings of the embodiments correspond to the same or similar parts; in the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for illustrative description, and cannot be understood as a limitation on the present patent, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0030] It has to be remarked that in the present text, the terms "comprising", "including", or any other variant thereof, are intended to cover a non-exclusive inclusion, such that processes, products or apparatuses that comprise a list of elements are not limited to those elements, but can include other elements not expressly listed or inherent to such processes, products or apparatuses. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, product or apparatus that includes the element.

[0031] The embodiment of the present application provides a comprehensive utilization method of sandy kaolin tailings, as shown in the figure, comprising the following steps: Figure 1 The embodiment of the present application provides a comprehensive utilization method of sandy kaolin tailings, as shown in the figure, comprising the following steps:

[0032] Step (1), the sandy kaolin tailings are screened into two particle size grades of +20 mesh coarse sand and -20 mesh fine sand;

[0033] Step (2), the +20 mesh coarse sand is ground by a high-alumina ceramic ball mill, and after grinding, the grading treatment is carried out to remove -140 mesh fine powder, and the grading product is obtained, and then the grading product is subjected to magnetic separation to remove magnetic minerals, and low-iron quartz sand for photovoltaic glass is obtained;

[0034] Step (3), the -20 mesh fine sand is also ground by a high-alumina ceramic ball mill, and after grinding, the grading and gravity separation treatment are carried out, and then the magnetic separation is carried out, and finally the obtained magnetic separation concentrate is subjected to positive flotation under neutral conditions to remove impurity minerals, and low-iron quartz sand for photovoltaic glass is obtained;

[0035] Step (4), the -140 mesh fine sand generated in the process of treating the +20 mesh coarse sand and the -20 mesh fine sand is subjected to magnetic separation, desliming, drying, powder grinding and grading treatment, and silicon micro powder is obtained.

[0036] The step (2) specifically comprises:

[0037] (1) the sandy kaolin tailings (the maximum particle is 2 mesh, the moisture is less than 10%, the SiO2 content is greater than 95%, the Al2O3 content is less than 2%, and the Fe2O3 content is less than 0.3%) are put into a vibrating screen with a screen hole of 20 mesh for wet screening, and the -20 mesh fine sand is removed, and the +20 mesh coarse sand is obtained;

[0038] (2) The +20 mesh coarse sand is ground by a high-aluminum ceramic ball (Al2O3 content greater than 90%) ball mill, the grinding concentration is 45%-60%, the ceramic ball filling rate is 40%-45%, the grinding product is classified by a cyclone, the cyclone underflow is fed to a high-frequency screen (mesh 35) for screening, the +35 mesh product is returned to the ball mill for recycling, and the cyclone overflow and the high-frequency screen undersize product are fed to a trommel screen (mesh 35), the +35 mesh product on the trommel screen is combined with the +35 mesh product on the high-frequency screen and returned to the ball mill for recycling, and the trommel screen undersize is a -35 mesh qualified product;

[0039] (3) The -35 mesh grinding product is subjected to hydroclassification to remove -140 mesh fine powder to obtain a classified product, and the classified product particle size is required to control the -140 mesh content to be less than 5%;

[0040] (4) The classified product is configured into a slurry with a concentration of 25%-30%, and is fed into a spiral chute to remove heavy minerals to obtain a gravity separation product;

[0041] (5) The classified product is subjected to magnetic separation to remove magnetic minerals in the classified product to obtain a magnetic separation concentrate. The magnetic separation is three stages, the first stage is a low-intensity magnetic separation with a magnetic field strength of 0.3-0.6 T, the second stage is a high-intensity magnetic separation with a magnetic field strength of 1.0-1.3 T, and the third stage is a magnetic separation with a magnetic field strength of 1.4-1.6 T. The quartz sand for photovoltaic glass (mass index: 35-140 mesh greater than 95%, SiO2 content 99.3-99.7%, Al2O3 content less than 0.20%, Fe2O3 content 0.008%-0.010%) is prepared.

[0042] Step (3) specifically comprises:

[0043] (1) The sandy kaolin tailings are subjected to wet screening by a vibrating screen to remove coarse sand with a particle size greater than 20 mesh to obtain fine sand with a particle size less than 20 mesh;

[0044] (2) The -20 mesh coarse sand is ground by a high-aluminum ceramic ball (Al2O3 content greater than 90%) ball mill, the grinding concentration is 45%-60%, the ceramic ball filling rate is 40%-45%, and the grinding product particle size is required to be less than 40 mesh; (since the particle size contains a large number of mineral solid inclusions, the grinding particle size is controlled to be less than 40 mesh to achieve sufficient dissociation).

[0045] (3) The -40 mesh grinding product is subjected to hydroclassification to remove -140 mesh fine powder to obtain a classified product. The classified product particle size is required to control the -140 mesh content to be less than 5%;

[0046] (4) The classified product is configured into a slurry with a concentration of 25%-30%, and is fed into a spiral chute to remove heavy minerals to obtain a gravity separation product;

[0047] (5) The classified product is subjected to magnetic separation to remove magnetic minerals in the classified product, to obtain magnetic separation concentrate. The magnetic separation is 3 stages, the first stage is magnetic magnetic separation, the magnetic field strength is 0.3-0.6T, the second stage is strong magnetic magnetic separation, the magnetic field strength is 1.0-1.3T, and the third stage is magnetic separation, the magnetic field strength is 1.4-1.6T; the magnetic separation concentrate (mass index: more than 95% of 40-140 mesh, SiO2 content 99.0%-99.3%, Al2O3 content 0.3%-0.5%, Fe2O3 content 0.012%-0.020%) is prepared.

[0048] (6) The obtained magnetic separation concentrate is further subjected to positive flotation of quartz under neutral conditions to remove impurity minerals such as muscovite and feldspar, and the specific method is as follows: the magnetic separation concentrate is configured into a slurry with a concentration of 25%-35%, the slurry is stirred, the pH value of the slurry is adjusted using NaOH, the pH value is controlled to be between 7-9, then cationic collector (a mixture of dodecylamine and octadecylamine 1:1) 50-100g / t, sodium oleate 100-200g / t are added in sequence, and the concentrate (mass index: more than 95% of 40-140 mesh, SiO2 content 99.3%-99.5%, Al2O3 content less than 0.20%, Fe2O3 content 0.008%-0.010%) is obtained by air flotation.

[0049] In order to prevent the first stage magnetic separator of the vertical ring from being blocked, the first stage magnetic separator is pulsed washed, and the pulse frequency is 100 times / min.

[0050] The second stage and the third stage strong magnetic separation are not pulsed washed; the medium box of the vertical ring magnetic separator is composed of stainless steel rods, and the diameter of the steel rods is 2mm.

[0051] The cationic amine collector is configured by amine and glacial acetic acid according to a molar ratio of 1:1. The flotation stage number is three, and the dosage of the collector is halved for each stage.

[0052] Step (4) specifically comprises:

[0053] (1) The -140 mesh fine sand obtained in steps (2, 3) is subjected to magnetic separation by a slurry magnetic separator, and the magnetic field strength is 1.3-1.6T.

[0054] (2) The magnetic separation concentrate is deslimed to remove -400 mesh fine mud, to obtain 140-400 mesh fine sand.

[0055] (3) The obtained fine sand is dewatered by a belt vacuum filter to a moisture content of less than 10%;

[0056] (4) The dewatered fine sand is dried by a roller dryer to obtain dried fine sand (moisture content less than 0.5%);

[0057] (5) The dried fine sand is fed into a ball mill for dry grinding. The ground silicon micro powder is then drawn into a classifier by the negative pressure generated by a blower. The coarser particles are returned to the ball mill for regrinding, forming a closed-loop cycle. The finer silicon micro powder is drawn into a cyclone collector for collection, thus obtaining silicon micro powder. By flexibly adjusting the grinding and classification parameters, silicon micro powder of different particle sizes can be produced.

[0058] Furthermore, according to Determine the optimal ball milling time t within the ball mill; where ρ is the density of the quartz sand, Q is the total throughput of the ball mill, V0 is the effective volume of the ball mill, C is the grinding concentration, R is the return sand ratio indicator, v is the volume of slurry passing through the ball mill per unit time, and V1 is the volume of slurry within the ball mill.

[0059] The slurry volume V1 inside the ball mill is positively correlated with the effective volume V0 of the ball mill in step two.

[0060] After determining the optimal ball milling time for the ore, laboratory grinding tests are conducted to find the optimal grinding time. This time is used as a reference, and the difference is compared with the calculated optimal ball milling time. Corrections are made based on the difference, which allows for precise control of the efficient operation of grinding operations in industrial production.

[0061] By measuring the operating time and total discharge volume of the ball mill, and combining this with the measured volume of slurry passing through the ball mill per unit time, the results are calculated and compared to determine whether the ore particles are continuously fed into the ball mill and discharged from the outlet without any stagnation.

[0062] Multiply the volume of slurry v passing through the ball mill per unit time by the operating time to obtain the theoretical total discharge volume for that time. Compare this with the actual total discharge volume to determine whether it is continuous. If the actual value is smaller, it indicates that it is not continuous.

[0063] With a density of quartz sand ρ = 2.65 t / m³ 3 For example, if laboratory grinding tests show that the optimal time is t = 6 min, then the grinding process parameters can be adjusted according to the formula:

[0064] (1) If V1 = 7.5m 3 Under the conditions of C=60% and R=30%, the optimal treatment rate should be adjusted to Q=55.3t / h;

[0065] (2) If V1 = 7.5m 3 Under the conditions of R=60% and Q=55.3t / h, the optimal grinding concentration should be calculated according to the formula to be C=68%.

[0066] (3) If V1 = 7.5m 3, C = 68%, Q = 75 t / h, should be calculated according to the formula, the optimal sand ratio is R = 17.9% under the condition of regulation.

[0067] Example, Guangdong kaolin tailings for example (1) kaolin tailings particle size element analysis data

[0068] Table 1 Guangdong kaolin tailings particle size chemical element analysis results

[0069]

[0070] From table 1, the quality of tailings of different particle size has obvious change, with the decrease of particle size, the content of Si O2 in tailings increases first and then decreases, Al2O3, Fe2O3, TiO2, K2O and other impurity elements show a trend of first decrease and then increase. Overall performance is the quality of coarse particle size of +20 purpose, the quality of fine particle size of-20 purpose is poor, which shows that the tailings has the potential of classification comprehensive utilization.

[0071] (2) beneficiation results

[0072] (1) +20 kaolin tailings beneficiation results

[0073] Test conditions:

[0074] (1) process flow "grinding-classification-reselection-medium magnetic (0.6T)-strong magnetic (1.3T)-strong magnetic (1.5T)"

[0075] (2) grinding conditions: grinding time 8 min, grinding product particle size 140-35 mesh more than 95%.

[0076] (3) magnetic separation conditions: medium magnetic magnetic separation pulse 100 times / min, strong magnetic magnetic separation without pulse.

[0077] The test results are as follows:

[0078] Serial number Sample name Sample number Total yield / % SiO2 / % Al203 / % Fe203 / % 1 +20 mesh tailings MM1-1 44.6 99.37 0.46 0.0328 3 Classified underflow MM1-2 39.0 99.50 0.21 0.0241 4 Classified overflow MM1-3 5.6 98.46 2.20 0.0934 5 Dense medium concentrate MM1-4 38.4 99.51 0.20 0.0219 6 Dense medium tailings MM1-5 0.6 96.24 0.85 0.1649 11 Medium magnetic concentrate MM1-6 36.9 99.55 0.18 0.0115 12 Medium magnetic tailings MM1-7 1.5 97.54 0.69 0.2778 15 High intensity 1 concentrate MM1-8 35.8 99.60 0.16 0.0105 16 High intensity 1 tailings MM1-9 1.1 98.93 0.83 0.0440 19 High intensity 2 concentrate MM1-10 35.1 99.62 0.15 0.0093 20 High intensity 2 tailings MM1-11 0.7 99.10 0.66 0.0707

[0079] (2) -20 kaolin tailings beneficiation results

[0080] Test conditions:

[0081] (1) process flow "grinding-classification-reselection-medium magnetic (0.6T)-strong magnetic (1.3T)-strong magnetic (1.5T)"

[0082] (2) grinding conditions: grinding time 10 min, grinding product particle size 140-40 mesh more than 95%.

[0083] (3) magnetic separation conditions: medium magnetic magnetic separation pulse 100 times / min, strong magnetic magnetic separation without pulse.

[0084] (4) Flotation conditions: pH 8.0, mixed amine 50 g / t, sodium oleate 100 g / t.

[0085] The test results are as follows:

[0086]

[0087] (3) Preparation of ceramic glaze powder from classified fine sand

[0088] The classified fine sand is produced by grinding and classifying the +20 mesh coarse sand and the -20 mesh fine sand, and the yield of the classified fine sand is 12.3%. The classified fine sand is subjected to magnetic separation by a slurry magnetic separator (magnetic field strength 1.4T), and the magnetic concentrate is subjected to "desliming-filtration dewatering-drying-grinding and classifying" to obtain -325 mesh silicon micro powder, and the specific indexes are shown in the following table. The quality meets the requirements of the ceramic glaze powder, and the -400 mesh fine mud is removed from the classified fine sand by desliming to prepare the silicon micro powder for the ceramic glaze.

[0089]

[0090]

[0091] The above merely describes the preferred embodiments of the present application, but not used to limit the protection scope of the present application.

Claims

1. A method for comprehensive utilization of sandy kaolin tailings, characterized in that, It comprises the following steps: Step (1), the sandy kaolin tailings are classified into +20 mesh coarse sand and -20 mesh fine sand; Step (2), the +20 mesh coarse sand is ground by a high-alumina ceramic ball mill, and after grinding, the product is classified to remove -140 mesh fine powder, and then the classified product is subjected to magnetic separation to remove magnetic minerals, thereby obtaining low-iron quartz sand for photovoltaic glass; Step (3), the -20 mesh fine sand is also ground by a high-alumina ceramic ball mill, and after grinding, the product is classified and subjected to gravity separation, and then subjected to magnetic separation, and finally the obtained magnetic separation concentrate is subjected to positive flotation under neutral conditions to remove impurity minerals, thereby obtaining low-iron quartz sand for photovoltaic glass; Step (4), the -140 mesh fine sand generated in the process of treating +20 mesh coarse sand and -20 mesh fine sand is subjected to magnetic separation, desliming, drying, grinding and classification, thereby obtaining silicon powder; In steps (2) and (3), the +20 mesh coarse sand is ground by a high-alumina ceramic ball mill, the grinding concentration is 45%-60%, the ceramic ball filling rate is 40%-45%, and the high-alumina ceramic ball has an Al2O3 content of more than 90%; the -20 mesh coarse sand is ground by a high-alumina ceramic ball mill, the grinding concentration is 45%-60%, the ceramic ball filling rate is 40%-45%, and the high-alumina ceramic ball has an Al2O3 content of more than 90%; In step (3), the product in the grinding process is classified by a cyclone, the underflow of the cyclone is fed into a high-frequency screen for screening, the +35 mesh product is returned to the ball mill for recycling, the overflow of the cyclone and the undersize product of the high-frequency screen are fed into a trommel screen, the +35 mesh product on the trommel screen is combined with the +35 mesh product on the high-frequency screen and returned to the ball mill for recycling, and the undersize product of the trommel screen is a -35 mesh qualified product, which is subjected to hydraulic classification to remove -140 mesh fine powder, thereby obtaining a classified product; the classified product is configured into a slurry with a concentration of 25%-30% and fed into a spiral chute for gravity separation; the gravity separation product is further subjected to magnetic separation, configured into a slurry with a concentration of 25%-35%, and adjusted to have a pH value of 7-9, and then cationic collector and sodium oleate are added to perform neutral positive flotation, thereby obtaining low-iron quartz sand for photovoltaic glass; In step (2), the product in the grinding process has a particle size of less than 40 mesh, which is controlled to less than 40 mesh to achieve complete dissociation; the product with a particle size of less than 40 mesh is subjected to hydraulic classification to remove -140 mesh fine powder, thereby obtaining a classified product; the classified product is configured into a slurry with a concentration of 25%-30% and fed into a spiral chute to remove heavy minerals, thereby obtaining a gravity separation product; the classified product is subjected to magnetic separation to remove magnetic minerals in the classified product, thereby obtaining low-iron quartz sand for photovoltaic glass; For the steps (2), (3), according to Determine the optimal ball milling time t in the ball mill; wherein p is the density of quartz sand, Q is the total amount of processing of the ball mill, C is the grinding concentration, R is the return sand ratio mark, V1 is the volume of the slurry in the ball mill; The -140 mesh fine sand in step (4) is subjected to magnetic separation at a magnetic field intensity of 1.3-1.6 T to obtain a magnetic separation concentrate; the magnetic separation concentrate is subjected to desliming treatment to remove -400 mesh fine slime to obtain 140-400 mesh fine sand; the obtained fine sand is dewatered to a moisture content of less than 10% by a belt vacuum filter and then dried to a moisture content of less than 0.5% by a roller dryer; the dried fine sand is fed into a ball mill for dry grinding, and the ground silica powder is classified by a classifier, and the relatively coarse particles are returned to the ball mill for regrinding to form a closed circuit, thereby obtaining silica powder of a required particle size specification.

2. The method for comprehensive utilization of sandy kaolin tailings according to claim 1, characterized in that, In step (1), the sandy kaolin tailings have a maximum particle size of 2 mesh, a moisture content of less than 10%, a SiO2 content of greater than 95%, an Al2O3 content of less than 2%, and an Fe2O3 content of less than 0.3%.

3. The method for comprehensive utilization of sandy kaolin tailings according to claim 2, characterized in that, In steps (2) and (3), the particle size requirement of the classified product is controlled to have a -140 mesh content of less than 5%; the magnetic separation is performed in 3 stages, namely, medium magnetic separation, two-stage strong magnetic separation, and magnetic separation.

4. The comprehensive utilization method of sandy kaolin tailings according to claim 3, characterized in that, In steps (2) and (3), the first-stage medium magnetic separation is performed at a magnetic field intensity of 0.3-0.6 T, the second-stage strong magnetic separation is performed at a magnetic field intensity of 1.0-1.3 T, and the third-stage magnetic separation is performed at a magnetic field intensity of 1.4-1.6 T.

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